Field of the Invention
The present invention provides azeotrope-like compositions of 1,1,1,2-tetrafluoropropene (HFO-1234yf) and 1,1,1,2-tetrafluoroethane (HFC-134a), and uses thereof, including use in refrigerant compositions, refrigeration systems, blowing agent compositions, and aerosol propellants.
Description of the Related Art
Fluorocarbon based fluids have found widespread use in industry in a number of applications, including as refrigerants, aerosol propellants, blowing agents, heat transfer media, and gaseous dielectrics. Because of the suspected environmental problems associated with the use of some of these fluids, including the relatively high global warming potentials associated therewith, it is desirable to use fluids having low or even zero ozone depletion potential, such as hydrofluorocarbons (“HFCs”), and low global warming potential. Thus, the use of fluids that do not contain chlorofluorocarbons (“CFCs”) or hydrochlorofluorocarbons (“HCFCs”) is desirable. The use of alkenes is also desirable due to there short atmospheric lifetime which results in a relatively low global warming potential. Additionally, the use of single component fluids or azeotropic mixtures, which do not fractionate on boiling and evaporation, is desirable. However, the identification of new, environmentally-safe, non-fractionating mixtures is complicated due to the fact that azeotrope formation is not readily predictable. The industry is continually seeking new fluorocarbon based mixtures that offer alternatives, and are considered environmentally safer substitutes for CFCs and HCFCs. Of particular interest are mixtures containing hydrofluorocarbons, hydrofluorolefins (“HFOs”) and other fluorinated compounds, which have a zero ozone depletion potentials and low global warming potential. Such mixtures are the subject of this invention.
The present invention provides compositions that help to satisfy the continuing need for alternatives to CFCs and HCFCs. According to certain embodiments, the present invention provides azeotrope-like compositions comprising of 1,1,1,2-tetrafluoropropene (HFO-1234yf) and 1,1,1,2-tetrafluoroethane (HFC-134a). The preferred compositions of the invention tend to exhibit relatively low global warming potentials (“GWPs”). Accordingly, such compositions can be used to great advantage in a number of applications, including as replacements for CFCs, HCFCs, and HFCs (such as HFC-134a) in refrigerant, aerosol, blowing agents, and other applications. This azeotrope-like composition can be used as a replacement in systems already utilizing HFC-134a where a significant reduction in GWP is desired. Additionally, it has been surprisingly found that azeotrope-like compositions of HFO-1234yf and HFC-134a can be formed. Accordingly, the present invention provides methods of producing an azeotrope-like composition comprising combining HFO-1234yf and HFC-134a in amounts effective to produce an azeotrope-like composition. In addition, it has been found that the azeotrope-like compositions of the present invention exhibit properties that make that make them advantageous for use as, or in, refrigerant, aerosol, and blowing agent compositions. Accordingly, in yet other embodiments, the present invention provides refrigerant compositions comprising an azeotrope-like composition of HFO-1234yf and HFC-134a.